Abstract:

Objective To analyze the epidemiological and etiological characteristics of hand, foot and mouth disease (HFMD) in Sichuan Province for evidences for scientific prevention and control of this infection. Methods The case data of HFMD in Sichuan Province registered in the Chinese Disease Prevention and Control Information System were retrieved from 2020 to 2024, and the pathological testing results of HFMD samples were collected from local Centers for Disease Control and Prevention (CDCs) in Sichuan. Descriptive epidemiology was used to analyze the epidemiological characteristics, and the seasonal distribution patterns were examined via seasonal index analysis. Results From 2020 to 2024, a cumulative total of 351 617 HFMD cases were reported in Sichuan Province, with an average annual incidence rate of 84.01/100 000. Of the reported cases, there were 161 severe cases and one death. Male and female cases numbered 201 178 and 150 439, respectively, with a sex ratio of 1.34∶1. The incidence rates for men and women were 95.23 and 72.55 per 100 000 population, respectively. Children under five years old constituted the majority of cases (299 509 cases, 85.18%), with the highest incidence rate observed in one-year-olds (2 891.03/100 000). Most cases occurred among children in home-based care (191 123 cases, 54.36%), though the proportion of student cases increased annually, reaching 12.02% by 2024. Seasonal analysis indicated bimodal incidence peaks in 2021 and 2023 and unimodal peaks in other years, with overall seasonal indices indicating elevated transmission from May to July and October to November. Geographically, annual incidence rates across prefectures ranged from 22.11 to 124.69 per 100 000 population, with the highest rates in Chengdu City (124.69/100 000), Panzhihua City (110.54/100 000), and Ya’an City (108.62/100 000). Pathogen distribution showed dominance by other enteroviruses in all years except 2024, when coxsackievirus A16 (CVA16) prevailed. Severe cases (including fatal) were most seen in children under three years old (135 cases, 83.33%), for which other enteroviruses were responsible (84.17%, 101/120). Conclusion HFMD in Sichuan Province peaks during summer and autumn, predominantly affecting infants and young children, with other enteroviruses as the leading pathogens. Our findings suggest that targeted prevention and control measures should prioritize high-risk populations during the peak seasons.

Key words: Hand, foot and mouth disease, Epidemiology, Enteroviruses, Coxsackievirus, Sichuan Province